Conjugation of biomolecules to solid surfaces is utilized in some forms of diagnostic applications, for example in immuno assays or nucleic acid arrays, both requiring the binding of a biomolecule to a solid phase. Different solid phase materials are available for various applications, including polystyrene or latex surfaces or particles, and also metal coated surfaces, metal particles and quantum dots, for example.
Among known metal nanoparticles, quantum dots and gold nanoparticles (AuNPs) gained particular attention due to their chemical inertness and the ease of surface modification (Mitchell, G. P. et al., J. Am. Chem. Soc. 121 (1999) 8122-8123; Mahtab, R. et al., J. Am. Chem. Soc. 117 (1995) 9099-9100; Mahtab, R. et al., J. Am. Chem. Soc. 122 (2000) 14-17; Reynolds III, R. A. et al., Pure Appl. Chem. 72 (2000) 229-235; Thanh, N. T. et al., Anal. Chem. 74 (2002) 1624-1628; Csáki, A. et al., Exp. Rev. Mol. Diagn. 2 (2002) 187-193; Thaxton, C. S., and Mirkin, C. A. in: Nanobiotechnology, Niemeyer, C. M., and Mirkin, C. A. (eds.), Wiley-VCH, Weinheim (2004) pp. 288-307).
For example, DNA may be coupled to gold nanoparticles. A DNA gold nanoparticle conjugate system (DNA-AuNPs) may be utilized for different applications e.g. for biosensors used for in vitro diagnostics, for in vivo imaging, as drug carrier, and for building up defined nanostructures, for example.